"That's why," he insists, "we aren't metal. [Not] like the stoners at the mall on a Friday night."

When Mastodon visits Colorado Springs this week, expect a swirl of gymnastic guitar, off-kilter drumming and on-stage stamina something the band members take more seriously than they do themselves.

"We could go out there and talk about tacos and beer farts," Sanders says, "but our art form is very serious to us. [Off-stage], we are four complete goofball idiots. Twenty-three hours a day, we are joking around, but that one hour a day, it's our chance to really go out there and be on our mark and just punish."

They'll let Ronnie James Dio sing about the dragons and wizards. Mastodon reaches its own brand of high-lonesome sound to dodge that stereotype.

"There is a touch of metal to us," acknowledges Sanders. But there's also, he adds, "a touch of classic rock, a touch of thrash, of punk. There are touches of classical guitars some of the guitar riffs will kind of stem from bluegrass riffs. There's a lot of '70s progressive rock in there, and there's a lot of jazz influences coming from our drummer many flavors and many threads."

The resulting tapestry is apparent on their latest album, Blood Mountain, which, according to the band's official bio, "[t]ells the story of a quest to ascend Blood Mountain to find a crystal skull, reach the top and insert the skull inside the band members' own heads in order to eradicate "reptile brain' and to transport them to the next phase of human evolution."

How positively un-metal is that?

Simultaneously claustrophobic and sprawling, Blood Mountain is a masterpiece that encompasses all the band's collective influences and creates with them an original musical journey. It earned Mastodon a spot on the Best Albums of 2006 lists from the New York Times and Rolling Stone, and a Grammy nomination for Best Metal Performance for the song "Colony of Birchmen."

However, "at the end of the day, [success] doesn't [matter]," Sanders says. "We hope that everyone likes us, but we know that we are not a band for everyone, by any means. So it's nice that your art is rewarded with very nice compliments. We tip our hats to [the critics], we thank them very much for acknowledging us, but we have to move on before it blows up our ego."

All this humility indeed seems to fly in the face of the metal ethos, where more is usually, well, more.

"In order to keep yourself in check, you really have to stay modest in the name of your art," Sanders says. "You know, we created this, from our hearts. It's what we feel is good, and it's a gigantic part of ourselves."

And if those warm-fuzzy remarks send Mastodon impossibly far from their brethren whatever genre they inhabit at least its bassist gets his edge back in the next sentence.

"We've been living, breathing, eating and shitting Mastodon for seven years straight now," Sanders says. "So when you put that much blood into it, I think the right word for it is "rewarding.'"